How to Ace the Chem/Phys Section of the MCAT


Preparing for the Medical College Admissions Test (MCAT) feels overwhelming, particularly if you don’t have a plan. In addition to understanding a lot of facts, you’ll also need to demonstrate your ability to reason and think critically about scientific information. As you begin your studying, it’s helpful to understand how the test is broken down and what you can do to excel in each section. The MCAT is made up of four sections:

Today, we’re going to focus on Chemical and Physical Foundations of Biological Systems (Chem/Phys). This section tests your knowledge a lot on concepts grounded in biology, chemistry, and physics. Chem/Phys is the first section you’ll encounter on test day. Being well-prepared for this section can help you gain confidence and create momentum that will help you succeed as you move through the entire test.


What’s on the Chem/Phys Section of the MCAT?

According to The Association of American Medical Colleges (AAMC),

The Chemical and Physical Foundations of Biological Systems section asks you to solve problems by combining your knowledge of chemical and physical foundational concepts with your scientific inquiry and reasoning skills. This section tests your understanding of the mechanical, physical, and biochemical functions of human tissues, organs, and organ systems. It also tests your knowledge of the basic chemical and physical principles that underlie the mechanisms operating in the human body and your ability to reason about and apply your understanding of these basic chemical and physical principles to living systems.


The Chem/Phys section accounts for 25% of the test, and you will be given 95 minutes to complete the 59 questions in the section. Possible scores on Chem/Phys range from 118-132. It’s made up of a combination of passage‐based and discrete questions.

This section tests introductory-level biology, organic and inorganic chemistry, physics concepts, first-semester biochemistry, molecular biology, research methods, and statistics concepts. It also requires you to show scientific inquiry and reasoning, research methods, and statistics skills as they relate to the natural sciences. The content breakdown for Chem/Phys is as follows:

  • 25% First-semester biochemistry
  • 5% Introductory biology
  • 30% General chemistry
  • 15% Organic chemistry
  • 25% Introductory physics

Chemical and Physical Foundations of Biological Systems

The following are the scientific inquiry and reasoning skills you’ll need to understand for the Chem/Phys section, according to AAMC:

  • Knowledge of Scientific Concepts and Principles: This includes demonstrating your understanding of the concepts and principles themselves as well as identifying relationships between concepts.
  • Scientific Reasoning and Problem-Solving: This includes reasoning when it comes to principles, theories, and models. You will also need to be able to analyze and evaluate scientific explanations and predictions.
  • Reasoning About the Design and Execution of Research: This includes understanding scientific research and being able to reason about ethical issues.
  • Data-Based and Statistical Reasoning: This includes interpreting tables, figures, and graphs. You’ll also need to be able to draw conclusions from and reason about data.

When taking this section of the MCAT, you will have access to a periodic table. However, you will not have access to a calculator or a formula sheet.

Finally, the Chem/Phys section tests your understanding of two foundational concepts:

  • Complex living organisms transport materials, sense their environment, process signals, and respond to changes using processes understood in terms of physical principles.
  • The principles that govern chemical interactions and reactions form the basis for a broader understanding of the molecular dynamics of living systems.

Being able to take this high-level overview of the content on the Chem/Phys section and turn it into a solid study plan is no easy task. You’ll find the most success on this section when you get help breaking down the concepts so you study the most valuable information. Next, we’ll provide tips, tricks, and resources to help you prepare for the Chem/Phys section of the MCAT.


How to Study for Chem/Phys

Studying for the Chem/Phys section involves memorizing information, applying information, and thinking critically. While critical reasoning and application are arguably more important, you also need to memorize enough information to have a basic understanding of the concepts tested in this section.

On the Chem/Phys section, you’ll find questions surrounding the following topics:

  • Forces
  • Work
  • Energy
  • Electrochemistry
  • How light and sound interact with matter
  • Atomic structure
  • Bonding and chemical interactions
  • Equilibrium
  • Acids and bases
  • Fluids
  • Waves and sound
  • Alcohols and ethers
  • Isomers
  • Laboratory techniques and separations
  • Enzymes
  • DNA
  • RNA
  • Kinetics
  • Carbonyl Chemistry

The above list is by no means exhaustive and is simply a sampling of the concepts you’ll encounter as you prepare for and take the Chem/Phys section of the MCAT.

Unsurprisingly, you simply cannot memorize every single fact or skill that may be tested on the MCAT. This is why you need to study high-yield material regardless of which section you’re preparing for. Tools like Memm help you break this information down so you’re studying what really matters. For best results, begin studying three to six months before you intend to take the test.

As you prepare for the Chem/Phys section, we recommend making liberal use of practice questions and practice tests. Practice questions are arguably most important for this section of the test, as you need to practice understanding questions and solving mathematical equations rather quickly. Memorizing facts will help, but applying what you learn with practice is where you’ll really start to see improvement.

It’s also important to keep in mind that in most cases, you will not be tested on information in a vacuum. The test is designed to assess how well you can think and analyze information, and many of the questions combine various sciences and concepts.

You can find practice questions and practice tests from third-party companies, but the most useful resources will come directly from the AAMC. Because these practice materials are made by the same people who make the actual test, they will be as similar to the real thing as possible.

In addition to learning the content you’ll need to know for this section, we also recommend strengthening your skills in two areas: understanding and applying equations and doing math without a calculator.

On the Chem/Phys section, you’ll need to know and use many physics equations. While some may be provided for you, this is not a guarantee, and you will not have access to a formula sheet. To succeed, you need to be well-versed in any equation you may encounter on the test. As you complete practice questions, make note of every equation you encounter. Practice using the equations so you can apply them quickly and efficiently when you encounter them on the test.

Another very important skill is being able to do basic math without a calculator. Not being prepared and practiced in this area can quickly eat up a lot of your time, and you may find that you run out of time to answer all the questions in this section. You’ll have less than two minutes to answer each question in the Chem/Phys section, so keep this in mind and do a lot of timed practice. The more you do math without a calculator, the faster you’ll get.

Particularly if you struggle with math, use answer options to your advantage. Because you don’t have a calculator, it’s a much better use of your time to round numbers when using an equation. If you look at the potential answers, you may be able to get an idea of a ballpark answer, and this can help you round numbers to make the math easier.


Resources for Chem/Phys

When you’re studying for Chem/Phys, you’ll make the most of your time and money if you focus on resources that help you study high-yield information. Here are some of the best resources for the Chem/Phys section of the MCAT:

Especially as you near test day, AAMC materials will be your best friend. They are most similar to the test, and they will help you adequately prepare.

Read our MCAT Study Guide which covers how the MCAT is scored, 7 MCAT study strategies, MCAT resources, FAQs, and more.


How to Succeed on the Chem/Phys Section

Most people spend a lot of money and a lot of time preparing to take the MCAT, and for good reason. This is one of the most important high-stakes tests you’ll take in your life. Many people feel the pressure and will do almost anything to get a good score. Thankfully, you don’t need to put your life on hold while studying for the MCAT if you study smartly.

Simplify the studying process by focusing on what is most important and honing skills that will help improve your score. When studying for Chem/Phys, start with a tool like Memm that will organize your studying and that provides you with high-quality cards and sheets. Once you’ve begun to review and memorize information, the AAMC materials will become your best friend as you train your mind for what it will encounter on test day.

Med School Insiders offers tailored MCAT tutoring designed around your strengths and weaknesses to help you make the greatest improvements. Learn more about our MCAT tutoring services and comprehensive admissions packages.


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